John f



UNITED STATES Cross Reference PATENT "OFFICE.

JOHN F. GESNER, OF NEW YORK, N. Y.

MANUFACTURE or ARTIFICIAL STONE.

SPECIFICATION forming part Of Patent No. 419,655, dated January 21, 1890. Application filed April 16,1888. Serial No. 270,854 (No specimens.)

1'0 all whom it may concern.-

Be it known that I, JOHN F. Gasman, of-

New York, in the county and State of New York, have invented a newand useful Im-' andspotash, didinarily known as soluble gtliagi are left exposed to ajgior some time t ey gradually lose a portion of their contained water from evaporation, dry to a certainextent, and acquire a considerable de gree of hardness. Especially is this the case if they have been previously mixed with a portion of earthy mineral matter not capable .of decompbi'ng them, such as eLy, chalk, .193: lfil l ialsstone, &c. At the same time such mixtures shrink and warp considerably in drying under ordinary circumstances, and

are consequently liable to get out of shape it molded in the ordinary way into any particular form or pattern. Mixtures of this kind sometimes become very hard, resembling stone, and may be used as such, or for cements where water is not liable to come in contact with them, but rapidly deteriorate when exposed to moisture, and are practically useless to withstand the climatic influences of the weather as artificial stone on'account of the solubility of the alkaline silicates contained in them. The soluble alkaline silicates, moreover, in said mixtures under ordinary atmospheric temperatures and conditions, and unless exposed to a temperature of I 212 Fahrenheit, or above, always retain a large proportion of combined water or water of crystallization. It is mixtures of this kind that it has hitherto been sought to decompose or render water-proof for use as artificial stone. For this purpose the mixture of solu-' ble glass and earthy mineral matters uch as chalk, clay, &e.- has been sprinkled while still wet, or after ordinary drying in the' air, with chloride of calcium or other decomposing-salt, or immersed in a solution of the same, for the purpose of decomposing the.

soluble silicate'in the mixture and precip'- tating an insoluble silicate in its place. On aecoun owever, o e wan of thorough Examiner dryness and lack of porosity of the material sought to be decomposed in this way for the formation of another insoluble material any decomposition that takes place under these circumstances is slight and merely superficial, and leaves the interior portion of the mass entirely untouched by the decomposing solution. To remedy this want of porosity, sand has been used to mix with the soluble glass with or without the addition of other mineral matter, and various devices have been employed to cause the solution of chloride of calcium or other decomposing solution to effect a more thorough decomposition of the material under treatment-such as forcing the decomposing solution into the mass by an air-pump, immersion of the material into the decomposing solution at 212, Fahrenheit, subjecting the molded mass to the action of the decomposing solution in close air-tight vessels above 212 Fahrenheit, or under steam-pressflre-but allto little avail. By the use of the sand, moreover, a coarse-grained stone only can in any case be formed,whereas by my process, on the contrary, I can make stone of the most pulverulent substances,

and consequently of the finest grain. Mixtures of soluble glass and mineral matter .have also been cast or molded first without the simultaneous application of heat or press-.

ure and then removed from the mold and dried in theair or by artificial means without being calcined, and the said mixtures have been vitrified at a baking heat in kilns, thereby rendering them both impervious to and undccomposable by the chemical agents I employ.

I have found by experiment that if soluble IO porosity and hardness during this process of calcination, it can be' made to retain any shape into which, while in a hydrous, soft, and plastic condition, it may originally have been molded. The confinement or pressure during calcination is for the purpose of cans: ing the material to retain the shape to which it has been cast or molded and to preserve a certain degree of density in it without impairing its porosity; but I can and do employ in certain applications the productmade with tony. uc'alsoiiasa' peculiarly Iiard aud"vit-"- the omission of the confinement or pressure. I have found that the porous material thus formed, being deprived of its moisture, is deprived of its liability to shrinkage or warping, and, furthermore, by reason of being porous and anhydrous throughout, it is pg culiarl ptssltebeinnrsg and W.

Tij any chemical agent which it" is to .be. "eoiivertedfromh soluble to an insoluble teens character, which it did not heretofore possess nor attain by ordinary drying, retaining this hardness to'a great extent after the soluble glass in it has been decomposed and replaced by other chemical substances. I may stop the process at this point and apply the product thereof to the arts, which' product may be varied by the use of soluble glass alone or in admixture with other mate- ;o rials. The product, however, at this point still contains the silicate in a soluble state, and I prefer to continue the process as follows to convert it into an insoluble body: I l lEsi-katheunaterielalr e y Brodlwed into whlerhmsqlutionnofana ihemi- Falbbd'fhiiing the property, of converting lglassinto, an insoluble body. or

fieo'iifi'tof the porosity of the calide'd material .and its dryness the converting solution is rapidly absorbed into itspores and a thorough conversion of its contained soluble glass is insured. The material still retains its porosity after the last treatment, and a thorough and rapid .removal'of the soluble salts resulting from thtmtmejfizahlfirad- Tly e co washlnmen taken from the bath of tlimposingsolution, a change is found to have taken place in the chemical and physical constitution of the material.

The soluble silicates have been re laced b silieaWother base, according xTtlfe charactei' of' the converting solution used. The excessive hardness and brittleness of the calcined material have disappeared and it has become considerably softer. It still retains, however,to a remarkable degree the peculiarly hard and compact character which it possessed when first taken from the calcining-press, if pressure had been employed in the calcining operation. The material resulting from the last operation may be applied to various uses; but I prcfeFtb wibjectittofirefillowing additional treatment, in order to expel from it the superfluous moisture it contains: For this purpose I submit it a gainjqh eaiand re spre, after sum-1 w prevent its again taking up water, I may fill its pores with a water-resisting substance? ""f Having thus outlined my process, I will proceed to describe more particularly each step and its variations.

For the production of materialwhich I can .lua mhlalqisl I pp y y process to soluble glass alone, being the ordinary commercial article of specific gravity from 35 to 40 Baum. This I do by first allowing a solution of it to dry in the air until sufiiciently hardened to be readily handled. It is then calcined under pressure, as more particularly described hereinafter. Generally, however, the same character of soluble glass will be treated in admixture with some solid s bstance or substances in a divided sfit',

witli'wliicii it is mixed in a pug mill or mixer until by evaporation or otherwise it has acdough, the proportions of which I vary at pleasure.

Tosubmit the soluble glass prepared as above, whether alone or in admixture, to calcination, I spread or place it between two 0pposite and parallel hot metallic molds or forms, which, corresponding in shape and pattern and fitting upon or into each other,

rated at pleasure by proper mechanical means.

The simplest form of press Imay use consists merely of two metallic plates, which are any exterior source of heat and t en placed horizontally one above and one below and in contact with the; material to be calcined, which I thus confine and calcine between and in contact with hot surfaces, the edges of the material being also preferably confined. The interior of these plates may be made hollow and capable of being filled with steam, &c., or of having heat communicated to them in place by any other appropriate means in circulation through them of hot air or hot liquids orby the contact of naked flames, &c. so asto avoid the necessity of removing them for the purpose of reheating them when they become cold. The most approved apparatus is described in my application for Letters Patent, Serial N 0. 271,523, filed April 23, 1888. In some cases in order to hasten the process I can be brought together in contact or sepaany other convenient manner-such asby the Ji l-"-3- quired the consistency of a stiff paste or of first heated to the reguired temperature by may effect a partial drying in the air of the soluble glass in admixture or otherwise after molding or pressing it into any given form or shape I may require it to take before submitt if 106. ccueosumus,

COMING R PLASllC Cross ting it to the joint action of heat and pressure, since when first exposed to a heat above 212 Fahrenheit as the soluble glass begins to lose its water of crystallization the partially dry and hard material becomes soft again and readily takes the required shape of the mold. In order to facilitate this preliminary drying, I may remove the material entirely from the mold or the mold partially or entirely from the material after casting and expose the material to the air or to artificial heat until it has set or hardened or acquired some degree of hardness from the evaporation of a portion of its contained water, when I return it to my molding-press to undergo my process of drying and calcinat-ion by the direct application of heat and pressure. I take care, however, not to allow the material so drying in the air, unless under pressure, to set or get so hard as not to become soft or somewhat plastic again when I place it in my molding-press, as it may warp and shrink so much, get so much out of shape, and lose so much moisture if too long exposed to the air after mixing as to become incapable of softening again sufficiently in the molding-press to flatten out again or to take the required shape of the mold. The proper and gradual drying and subsequent ealcination of the material, while preserving at the same time its original form or pattern that may have been given to it, requires some degree of skill, which can be readily acquired by a little practice and experience.

Having placed my mixture of soluble glass then in what I will hereinafter denominate my calcining-press, I first apply to the plates of said press and keep up a temperature a little below or about 212 Fahrenheit until I have expelled superfluous mechanically-contained moisture from the material, or until I have brought about the solidification of the soluble glass contained therein, if this has not sufiiciently hardened by having been previously air-dried or reduced to the ordinary state of dryness, which it gradually attains after a few days exposure to a dry atmosphere of average temperature.

To prevent the material adhering to the plates of the press during the process of drying and subsquent calcination, I sprinkle plcntifully both the plates of the press with which the material may be brought in contact and .the material itself with fine dry powdered chalk, clay, silica, &c., or other fine dry absorptive mineral matter, or I whitewash the sides of my press with the same and allow it to dry, or I may inter-pose cloth well dusted over with the said dry mineral matter between the material to be dried and calcined and the plates of the press, and which may afterwarilbe readily stripped from the material. then keep graduall 'easin the heat above the tempmturfi 2 ahreneituntil all the com I u or water of crystallization of the soluble glass under treatment has been expelled in the Reference state of vapor and it has attaineiamery porous and e steetlreflrdeeas ammu- Trs lglat uaI increase 6f heat canbe conven- Examiner ieutly effected by carefully regulating by means of a stop-cock the amount and pressure of the steam admitted to the hollow plates of the calcining-press. In some cases I may use superheated steam in my press when a high temperature is required.

During the process of gradually expelling the combined water from the soluble glass in the mixture by a gradually-increasing temperature from 212 Fahrenheit upward under pressure an infinite number of vaporvesicles are formed, and owing to the nature of the material these are caught and imprisoned in its substance as it gradually acquires an increasing degree of hardness from the expulsion of water. These vapor-vesicles con; stitute a multlllQQ QXtPQm X- Q pores, whidfij'finaiiy'coalescing afl'd'dommunicating with one another to a greater or less extent fiiroi'i'glibhmie mass of the material during the process, afford a-means of escape to the exterior for all interiorlyconfined moisture. The material thus attains a state of porosity .or cellular structure similar to that which well-leavened'bread acquires in the processes of raising and baking. The ressure or confinement to which it is en jected in the meantime prevents the soluble glass from attaining the formless spongy condition which it would otherwise do, and stamps and leaves upon it the original impression or pattern of the calcining-press.

The object of gradually raising .the heat is to give time for the moisture-near the surface to escape first through the porous substance of the material thus formed, and by degrees in this way to work toward and into the interior of the material. Some skill and judgement are required here to avoid forcing the process or raising the heat too rapidly and too high, as in this case the material may become so spongy and porous as to lose proper solidity and tenacity. On the other hand, if the applied heat be -not high enough or not maintained a suificient length of time, the material will not be thoroughly calcined, and ther'eforenot susceptible of subsequent thorough decomposition. No harm to the mater' can result from an unnecessarily-long ex-.

position or vitrificaIidfnm.

ressnr e'and heat must be so adapted to each other and the duration of their application so adjusted that the material may not -lose density and firmness, while retaining at may ultimately raise the plates of my calcining-press and the time required for its application will depend entirely upon the kind and the thickness of the material to be treated confined between them.

To treat a mixture of one inch, or thereabout, in thickness, I may employ a gradual, increase of heat, after ordinary drying or setting, fromh2li2 Fahrenheit to between400 an 500 or ig ier for twelve hours. n 18 case I may us'eifiperheated steam for the heating medium in my calcining-press. If the higher temperature 'above given would be destructive of the ingredients mixed with the soluble glass, the temperature must be confined to the lower degrees. I continue the heat applied to my calcining-press at its maximum for a considerable time after there is no longer any evidence of escaping steam or moisture from the mixture, when the process is finished.

The amount of pressure required to be exerted on the material by the plates of the calcining-press will depend upon the kind of material to be treat-ed and the sort of product desired. Simple close confinement may sometimes be sufficient, if the material be thin, of small superficial dimensions, and not to be impressed with any pattern, but made plain or fiat, or if the objectof the applied pressure or confinement be merely to keep the material in shape and to prevent its putfing up too much. If a pattern is to be stamped upon it, however, some pressure will be required, and this will vary somewhat according to the thickness and bulk of the material, the greater the thickness and superficial dimensions of the material the greater will be the pressure required, and vice versa. The pressure applied must be sufficient to oifset at first the expansion of the material, and as it afterward shrinks the pressure must be maintained upon it to cause it to take and retain a sharp impression of the mold.

If a material of greater density be required, hydrau 1 r similar pressure may be applied during the process of calcination, care being taken in this case to increase the temperature gradually, so as to allow the vapor generated to escape slowly, regularly, and by degrees in small portions at a time. The greater the applied pressure the longer time it will require to calcine the material and the denser will be the resulting product; but the pressure or confinement must never be so great as not readily to allow of the free escape of vapor from the material itself. The pressure upon the plates of said press should be elastic enough to yield somewhat against the expansion of the material as it begins at first to part with its combined water, and, while strong enough to follow up and maintain a pressure upon the said material as it afterward contracts from the expulsion and loss of said water, not so strong as to confine the escaping steam too much.

the part of the intelligent workman will soon enable him to judge correctly of the intensity of the heat and the time and pressure required for the particular kind and thickness of material he may be treating.

When I take the material from my calcining-press, I find that it has undergone a great physical change. It has become much harder than before and of an entirely diiferent character from ordinary dry mixture of soluble glass which have hitherto been known and obtained by drying the same in the air. There has been set up in it a highly porous and absorbent condition similar to that of earthenware or porcelain in the state of biscuit preparatory to glazing. Although very porous, the material has become very solid, harsh, and gritty, so as to quickly wear away any edge-tool that may be employed to cut or saw it.

Having thus applied the first step of my process, I will now describe particularly the application of the step which converts the soluble glass in my material into insoluble matter.

In order to render m material essentially waterfimfifimuimumncafes in it must be replaced by other compounds which are insoluble, and this is elfected by bringing it in contact with solution of chem i camsrcapable OfflQCQHlPosingsoln;

'ble glass. Hit err-o chloride of cerium has bee'fichiefiy recommended or used for this purpose, although a few other salts have also been suggested. I have found by careful experiment that besides these a large number of other chemical compounds in solution are capable of efiect-ing this decomposition. Such are the ordinary free acids and the soluble oxides and salts of the metals other than those generally of the alkaline metals, except some of these in double salts, as in some of the socalled alums. Among the most important and availabl'c?f these are 'soluble free acids: sul huric,hy rochloricmgfiztartafim oxalic, po io, citric, phosphoric, sulphurous, We, arsenic; soluble oxi es: barium ydroxide, strontium hydroxide, chromium trioxide, or chromic acid; soluble salts: calcium, nitrite, hypophosphite, hyposulphite, sulphide, acetate, chloride; strontium: chloride, nitrate; barium: chloride, nitrate, sulphide; magnesium: chloride, hypochlorite, sulphite, hyposulphite, sulphate, nitrate, acetate, phos'phite, hypophosphite, tungstate; zinc: chloride, sulphate, acetate, sulphite, nitrate, hypophospite, chlorate; lead: nitrate, acetate; copper: chloride, s lphate, nitrate, acetate; merczry: bic loridiz aluminum: sulphate, acetate chlorid nitr e,hyposulphite, hydrochlorite, sulphite; manganese: chloride,

sulphate, acetate; iron: chloride, sulphate,

nitrate, acetate, sulphite; nickel: chloride, sulphate, nitrate, acetate; chromium: sulphate, potassium and chromium sulphate, ammonium and chromium sulphate, potassium A little experience in practical working on bichromate, sodium bichromate; tin: proto i comma ORPLASIlC rieierence chloride, sulphate, hyposulphite; antimony:

' antimony and potassium tartrate. .Besides these there are some chemical compounds and mixtures which can best be described by their ordinary commercial names, such as superphosphate of lime, bisulphite of lime,

i chloride of lime or bleaching-powder, pyrolignito of lime, the alums, aluminous cake,

I &c. Other decomposing compounds may be rpiound cheaper and more available in the f uure.

I do not confine myself to decomposing compounds that are soluble in water only, or

to aqueous solutions of the same merely; but I may sometimes use as'solvents for my decomposing agents other menstrua, such as acids,

alkalies,alcohol, &c. I therefore in the dry calcined and pressed condition of my material, which I have described, immerse it into a saturated cold or hot solution of the kind of chemicalji0d1s'Ilftwe'tmflici'tedTOfi'iic count of'the greatp" orositywfTliebalcined material thus prepared and its perfect dryness, the decomposing solution is rapidly ab- 2 5 sorbed into its pores and a thorough decomposition of its contain ed soluble glass insured. Moreover, the material still retaining its porosity after decomposition, a thorough and rapid removal of the soluble salts resulting from the said decomposition can be readily effected by washing. The time necessary for its Wwill depend upon the an ness of material to be treated; but generally from six hoprs to 3 5 twenty-four hours will be smt. The char'at'zter of the ecomposition which takes place will depend gpoilifthg kind of decomposing so ution use a ilu acid be employed, it abstracts sodafoTpdt sh from the 0 alkaline silicate in the mixture, forming a soluble salt, and precipitates free insoluble acid ch rac or e used,1 abstrac the silica or silicic acid from the alkaline silicate, forming an WWW which is precipitated, whi e so uble so a or potash is set free. If a aim a metallic salt be the decomposing agentWr ntal-es dou blecompositio' place, the silica in v e so u e g ass abstract- We base of the metallic salt, forming an insoluble silicate, which precipitates, while the acid of the metallic salt thus set free com: bines' with the freed base of the alkaline silicate, forming a soluble salt. The choice of these and other similar decomposing soluble substances will depend upon their cheapness and availability. Care' must be taken in their selection not to employ one which is apt to exert a decomposing action upon any one of the ingredients in the mixture under treatment. I prefer for general use an aqueous solution of a metallic salt with an acid reaction, such as fe rous sulphate, aluminum sulphate, the alums, 2C0. I stronger and better ds productms-to result from the use of this kind of decomposing agent, from the consequent precipitation of an insoluble m}etallic referred to above, I may in some cases, in

silicate, than from that resulting from the use of dilute acids, where merely insoluble silica is precipitated. It is now desirable to wash out the soluble oxides or sa s con 'uned in t e rialfim'ohip'fess and dry it, although in some cases, where the retention of the soluble salts would not interfere with its appearance or applications, it may be compressed and dried at once for use without further treatment. IIeretofore washing has been effected by immersion of the material fora time in still or running water or exposure to the action of steam, and this for ordinary purposes may be sufficient; but when a fine product is to be produced that will not efiloresce I have found that spraying water in fine jets on the material is more effective,besides resulting in a great saving of water, which is sometimes an item of expense. For this purpose I hang upthe material to be washed in a chamber where finejets of water are arranged to play in a spray upon it for from six to twenty-four hours, according to the thickness of material, or until it is sufficiently free from soluble substances.

The decomposed material when first taken from the decomposing-bath, or after washing to remove the soluble salts in it, is so thoroughly saturated with moisture that it may be somewhat spongy and fragile, and liable also to lose somewhat on this account its original form or shape, especially if it has been molded to any fine pattern. To make it retain its original shape or form to which it may have been molded, to increase its density, and to expel from it all superfluous moisture, I may again submit it to pressure... ()5 o and heat in the same pres orin a similar x mu I have already used for calcining it, and which I have described above as my calcining-press. In this part of my process I may also use hydraulic pressure in a hydraulic or other press with or without the aid of heat, so as materially to increase the density and hardness of the material thus treated. As the material after this treatment still remains very porous, unless it has been previously submitted to hydraulic pressure,

for the latter purpose n med are melted or dissol ed W t, drying-oils melted or ii ssrlw u 'a-ruli- 1 0 b9; and gutta-perchaTQ fuSeH oiilismfiid lipiltgwaps or insblifble mefilhc i ole-a es or stearafifacwwimmr other solutionsdf thercsin's, gumsdtc.

LMluuuw The material when complete in its framework or structure by which the whole is knit together consists of an insoluble compound of silicon (silica or silicate of lime, the.) in a porous or cellular condition. With this frame-work may be combined some water-resisting substance injected into the pores, and there may also be combined foreign solid substances between the particles of which the insoluble compound of silicon occupies the relationship of a skeleton or frame-work uniting or cementing the whole together.

I claim-- 1. In the process of manufacturing artificial stone, heating soluble alkaline silicates to a temperature between the volatilizing temperature of the solvent and the heat of vitrification until the solvent is expelled.

2.- In the process of manufacturing artificial stone, heating the soluble silicates under confinement.

3. In the process of manufacturing artificial stone, first drying a solution of soluble silicates and then heating the same while under confinement.

4. In the process of manufacturing arti fieial stone, heating the soluble silicates while the latter are subjected to pressure which follows up the shrinkage of the material.

5. In the process of manufacturing artificial stone, first drying a solution of the soluble silicates and then applying a gradually-increasing heat ranging from the volatilizing temperature of the solvent upward while under confinement.

6. In the manufacture of artificial stone,

- expelling the solvent from the soluble alkaline silicates, leaving the alkaline silicate porous, and then introducing a converting agent into the pores to render the material insoluble.

3. In the manufacture of artificial stone, expelling the solvent from soluble alkaline silicates by the application of heatandpressure, whereby the alkaline silicate is left porous, and then rendering the same insoluble by the introduction of a converting agent into the pores thereof.

9. In the manufacture of artificial stone,

expelling the solvent from the soluble alkaline silicates, whereby the alkaline silicate is left porous, then rendering the same insoluble by the introduction of a converting agent into the pores, and then drying the same under pressure.

10. In the manufacture of artificial stone, expelling the solvent from the soluble alkaline silicates, leaving the same porous, then rendering them insoluble by the introduction of a converting agent into the pores, and then removing the soluble salts from the pores by washing. r

11. In the manufacture of artificial stone, expelling the solvent from the soluble alkaline silicates, leaving the same porous, then rendering them insoluble by the introduction of a converting agent into the pores, and then filling the pores with a water-resisting subsolution a coloring-matter, and then subjecting them to heat and pressure to expel the solvent.

JOHN F. GESNER.

\Vitnesses:

D. II. DRISCOLL, I J. E. GREER. 

